Acrylic pressure-sensitive adhesive for promoting gas discharge and application thereof

Abstract

The present invention relates to an acrylic pressure-sensitive adhesive for promoting gas discharge, comprising 100 parts by weight of an acrylic prepolymer, 0.01-1 parts by weight of a first photoinitiator and 0.05-2 parts by weight of a cross-linking agent; based on the acrylic prepolymer, the acrylic prepolymer comprises: 1-90 parts by weight of at least two acrylic monomers, and 0.05-2 parts by weight of a second photoinitiator. The present invention optimizes the molecular structure of the acrylic pressure-sensitive adhesive to improve its fluidity and aging resistance, thereby obtaining an acrylic pressure-sensitive adhesive with good stability and bonding performance and no bubble rebound under high temperature and high humidity conditions, and is applied to an attached object that is prone to generate gas under high temperature and high humidity conditions, thereby solving the problem that traditional acrylic pressure-sensitive adhesives cannot discharge the gas generated by the attached object in the optical device manufacturing process, thereby causing bubble rebound.

Description

Technical Field

[0001] The invention relates to the field of OCA optical adhesives, and in particular to an acrylic pressure-sensitive adhesive for promoting gas discharge. Background Art

[0002] As a human-computer interaction window, the touch display screen is currently the simplest and most natural input device, and there is also huge room for development in the research of its component materials. In the production and manufacturing process of the screen, adhesive materials play an important role, and their performance has a certain impact on the overall performance and service life of the screen. Optical adhesive (OCA) is a multifunctional substrate-free adhesive material. Due to its good optical properties and adhesion, it has become the preferred adhesive material on the market. When bonding the screen, optical adhesive can effectively fill the tiny gap between the screen and the touch layer, improve the display effect and touch sensitivity, while providing protection for the screen and extending the service life of the screen.

[0003] Acrylic pressure-sensitive adhesives among optical adhesives occupy an important position in the screen bonding market due to their advantages such as simple formula, wide bonding range and low cost. However, most acrylic pressure-sensitive adhesives perform poorly in practical applications of bonding optical components such as polycarbonate and acrylic due to their poor gas exhaust performance and aging resistance. Usually, acrylic pressure-sensitive adhesives cannot exhaust the gas generated by such adhered objects under high temperature and high humidity conditions, causing bubbles to rebound on the bonding surface. This problem limits the development and utilization of acrylic pressure-sensitive adhesives. Therefore, it is challenging to prepare acrylic pressure-sensitive adhesives that promote gas exhaust by a simple method for bonding optical devices that are prone to backbubbling under high temperature and high humidity environments. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing an acrylic pressure-sensitive adhesive that promotes gas discharge. By regulating the molecular structure, the fluidity of the acrylic pressure-sensitive adhesive is improved, and the acrylic pressure-sensitive adhesive has good stability and bonding ability in a high temperature and high humidity environment, without the problem of bubble rebound, and can be used for optical components such as polycarbonate and acrylic that are prone to generate gas in a high temperature and high humidity environment.

[0005] In order to solve the above technical problems, the present invention provides an acrylic pressure-sensitive adhesive for promoting gas discharge, characterized in that the acrylic pressure-sensitive adhesive comprises:

[0006] Acrylate prepolymer 100 parts by weight;

[0007] The first photoinitiator 0.01-1 parts by weight;

[0008] Cross-linking agent 0.05-2 parts by weight.

[0009] Furthermore, the first photoinitiator includes at least one of (2,4,6-trimethylbenzoyl)di(p-tolyl)phosphine oxide (TMO), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester (TPO-L), hydroxycyclohexane phenone (184), benzophenone (BP), and 2,2-dimethoxy-2-phenylacetophenone (651).

[0010] Furthermore, the crosslinking agent includes at least one of 1,6-hexanediol diacrylate (HDDA), triethylene glycol diacrylate (TEGDA), tripropylene glycol diacrylate (TPGDA), (2) propoxylated neopentyl glycol diacrylate (NPG (2) PODA), acrylic polybutadiene (BAC-15, Mw = 1200), acrylic polybutadiene (BAC-45, Mw = 2800), 1,9 nonanediol dimethacrylate, polyvinyl alcohol (600) diacrylate (PEG (600) DA), (20) ethoxylated bisphenol A diacrylate (BPA (20) EODA), (6) ethoxylated bisphenol fluorene diacrylate (BPF (6) EODA), (10) ethoxylated bisphenol A dimethacrylate (BPA (6) EODMA), and (30) ethoxylated bisphenol A diacrylate (BPA (30) EODA).

[0011] Further, the acrylate prepolymer comprises:

[0012] 1-90 parts by weight of at least two acrylate monomers;

[0013] The second photoinitiator is 0.05-2 parts by weight.

[0014] Further, the acrylate monomer includes at least two of isodecyl acrylate (IDA), trimethylcyclohexyl acrylate (TMCHA), lauryl acrylate (LA), acryloyl morpholine (ACMO), octyl acrylate (IOA), butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA), lauryl methacrylate (LMA), 2-phenoxyethyl acrylate (PHEA), isobornyl acrylate (IBOA), and methyl methacrylate (MMA).

[0015] Furthermore, the second photoinitiator includes at least one of (2,4,6-trimethylbenzoyl)di(p-tolyl)phosphine oxide (TMO), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester (TPO-L), hydroxycyclohexane phenone (184), benzophenone (BP), and 2,2-dimethoxy-2-phenylacetophenone (651).

[0016] The present invention provides an acrylic pressure-sensitive adhesive for promoting gas discharge, which can be used for bonding optical components that are prone to generate gas in high-temperature and high-humidity environments such as polycarbonate and acrylic.

[0017] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0018] The present invention optimizes the molecular structure of the acrylic pressure-sensitive adhesive and improves the fluidity of the pressure-sensitive adhesive by selecting acrylate monomers and long-chain cross-linking agents with low polarity and strong chain segment mobility. The actual application is illustrated by bonding a polycarbonate screen. Based on the above technical improvements, under high temperature and high humidity conditions, the pressure-sensitive adhesive bonded to the polycarbonate screen can use its good fluidity to discharge gas from the inside of the pressure-sensitive adhesive, thereby preventing gas accumulation on the bonding surface of the pressure-sensitive adhesive and bubble rebound. The acrylic pressure-sensitive adhesive can solve the problem that traditional acrylic pressure-sensitive adhesives are difficult to discharge the gas generated by some optical devices under high temperature and high humidity, resulting in bubble rebound at the bonding interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The storage modulus diagram of the embodiment of the present invention and the comparative example is

[0020] Figure 2 The aging test diagram of the embodiment and the comparative example of the present invention is shown in FIG. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0022] Table 1: Ratio and dosage of each substance component in the embodiments and comparative examples (unit, mass parts)

[0023]

[0024] Example

[0025] According to Table 1, the acrylic monomer and the second photoinitiator were accurately weighed, added to the reaction kettle, nitrogen was introduced at the same time, and the ultraviolet lamp was turned on for reaction after stirring for 20 minutes to obtain an acrylate prepolymer. Then, 100 parts of the prepared acrylate copolymer (calculated by solid content) were added with a proportion of the crosslinking agent and the first photoinitiator, stirred thoroughly, and then vacuum defoamed. Then, a coating machine was used to coat the 75 μm release film and the 75 μm PET substrate, and the mixture was placed in a UV light box for curing for 6 minutes, so that the thickness of the dried film was 175 μm.

[0026] Comparative Example

[0027] Accurately weigh the components according to Table 1. The preparation method refers to the example.

[0028] Test items

[0029] Storage modulus test: remove the PET release films on both sides of the prepared test sample, overlap multiple film layers to obtain a sample with a thickness of ≥1000μm, and cut it into a disc with a diameter of 8mm. Use a rheometer (Thermo Fisher, model: HAAKEMARS40) to test the storage modulus at different temperatures. The measurement frequency is 1Hz, and the measured storage modulus value is recorded in kPa.

[0030] Aging resistance test: The prepared OCA sample was laminated with a polycarbonate sheet and a glass sheet in turn, vacuum degassed for 30 minutes and then left to rest for 24 hours, and then placed in an aging test chamber for a high temperature and high humidity test. The high temperature and high humidity test was conducted by placing the sample at a temperature of 85°C and a humidity of 85% for 48 hours.

[0031] The storage modulus of the acrylic pressure-sensitive adhesives obtained from the tested examples and comparative examples at different temperatures are shown in Table 2.

[0032] Table 2

[0033]

[0034] From Table 2 and Figure 1 The test results show that the storage modulus of the acrylic pressure-sensitive adhesive prepared in the embodiment of the present invention is relatively low, indicating that it has good fluidity and is conducive to the discharge of bubbles in a high temperature and high humidity environment. Moreover, the storage modulus of the acrylic pressure-sensitive adhesive prepared in the comparative example is higher than that of the embodiment at all temperatures, indicating that it has a higher hardness and poor mobility of the colloidal molecules. Figure 2 The results show that after the aging test, the acrylic pressure-sensitive adhesive prepared in the embodiment can use its fluidity to discharge the gas generated by the adhered object in a high temperature and high humidity environment, and there is no bubble rebound on the bonding surface, while the acrylic pressure-sensitive adhesive with a higher modulus prepared in the comparative example has bubble rebound on the bonding surface.

[0035] In summary, by optimizing the molecular structure of acrylic pressure-sensitive adhesive and improving its fluidity, an acrylic pressure-sensitive adhesive with good aging resistance and bonding properties and no bubble rebound in high temperature and high humidity environments can be obtained.

[0036] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An acrylic pressure-sensitive adhesive for promoting gas discharge, characterized in that: The acrylic pressure-sensitive adhesive comprises: Acrylate prepolymer 100 parts by weight; The first photoinitiator 0.01-1 parts by weight; Cross-linking agent 0.05-2 parts by weight.

2. An acrylic pressure-sensitive adhesive for promoting gas discharge according to claim 1, characterized in that: The first photoinitiator includes at least one of (2,4,6-trimethylbenzoyl)di(p-tolyl)phosphine oxide (TMO), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester (TPO-L), hydroxycyclohexane phenyl ketone (184), benzophenone (BP), and 2,2-dimethoxy-2-phenylacetophenone (651).

3. The acrylic pressure-sensitive adhesive for promoting gas discharge according to claim 1, characterized in that: The crosslinking agent includes at least one of 1,6-hexanediol diacrylate (HDDA), triethylene glycol diacrylate (TEGDA), tripropylene glycol diacrylate (TPGDA), (2) propoxylated neopentyl glycol diacrylate (NPG (2) PODA), acrylic polybutadiene (BAC-15, Mw=1200), acrylic polybutadiene (BAC-45, Mw=2800), 1,9 nonanediol dimethacrylate, polyvinyl alcohol (600) diacrylate (PEG (600) DA), (20) ethoxylated bisphenol A diacrylate (BPA (20) EODA), (6) ethoxylated bisphenol fluorene diacrylate (BPF (6) EODA), (10) ethoxylated bisphenol A dimethacrylate (BPA (6) EODMA), and (30) ethoxylated bisphenol A diacrylate (BPA (30) EODA).

4. The acrylic pressure-sensitive adhesive for promoting gas discharge according to claim 1, characterized in that: The acrylate prepolymer comprises: 1-90 parts by weight of at least two acrylate monomers; The second photoinitiator is 0.05-2 parts by weight.

5. The acrylic pressure-sensitive adhesive for promoting gas discharge according to claim 4, characterized in that: The acrylate monomers include at least two of isodecyl acrylate (IDA), trimethylcyclohexyl acrylate (TMCHA), lauryl acrylate (LA), acryloyl morpholine (ACMO), octyl acrylate (IOA), butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA), lauryl methacrylate (LMA), 2-phenoxyethyl acrylate (PHEA), isobornyl acrylate (IBOA), and methyl methacrylate (MMA).

6. The acrylic pressure-sensitive adhesive for promoting gas discharge according to claim 4, characterized in that: The second photoinitiator includes at least one of (2,4,6-trimethylbenzoyl)di(p-tolyl)phosphine oxide (TMO), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester (TPO-L), hydroxycyclohexane phenyl ketone (184), benzophenone (BP), and 2,2-dimethoxy-2-phenylacetophenone (651).

7. The acrylic pressure-sensitive adhesive for promoting gas discharge as claimed in any one of claims 1 to 6 is used for bonding optical components that are prone to generate gas in a high temperature and high humidity environment of polycarbonate (PC) or acrylic (PMMA).

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